Driving roller assembly for paper feeding apparatus

ABSTRACT

A driving roller assembly for a paper feeding apparatus is provided for driving a driving roller to move a piece of paper. The assembly includes a transmitting sleeve, a one-way coupling sleeve, and a driven block. The transmitting sleeve is provided for moving the one-way coupling sleeve to be engaged with the driven block, and driving the one-way coupling sleeve to rotate. The one-way coupling sleeve is coupled to the driven block for rotating the driven block in one rotational direction only, and thereby driving the driving roller to rotate. When the rotational speed of the driving roller is higher than that of the transmitting sleeve, or the transmitting sleeve stops rotating, the driving roller is rotated by other external force without interfering with the transmitting sleeve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 095213169 filed in Taiwan, R.O.C. on Jul. 26, 2006, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a paper feeding apparatus for a printer or a scanner, and more particularly, to a driving roller assembly for a paper feeding apparatus that has a simple mechanism and is used to prevent paper jams from occurring.

2. Related Art

Currently, the paper feeding rate of an automatic document feeding apparatus has been well enhanced. If a second piece of paper has to be taken and scanned/printed after the first piece of paper has been completely scanned/ printed, the interval between the two pieces of paper is excessively large, and thus, the paper feeding rate and scanning/printing rate cannot be effectively improved. Therefore, the cooperation of the rotational speed of the paper-grabbing roller set with that of the rotational speed of the paper-feeding roller set has become an important issue. Generally, the rotational speed of the driving roller in the paper-grabbing roller set is lower than that of the driving roller in the paper-feeding roller set, such that the paper feeding rate of the paper-grabbing roller set is lower than that of the paper feeding rate, and thus there is a predetermined interval between two pieces of paper due to the difference of the paper feeding rate. However, the higher paper feeding rate and the lower paper feeding rate lead to an interference between the paper-grabbing roller set and the paper-feeding roller set, i.e., when the front edge of a piece of paper reaches the paper-feeding roller set, the middle and rear sections of the paper are still under the control of the paper-grabbing roller set. Thus, the two roller sets are interfered with each other due to the rotational speed difference, and relative sliding occurs between the paper and the driving roller of the paper-grabbing roller set, and thereby resulting in crumpling or even tearing of the paper. Therefore, it has become an important technical subject to prevent the paper from being damaged by the interference between the paper-grabbing roller set and the paper-feeding roller set due to the paper feeding rate difference.

In the conventional art, the driving roller of the paper-grabbing roller set is generally shaped as a cylinder or a semi-cylinder. When the driving roller with a shape of the semi-cylinder grabs paper, the outer periphery of the semicircular part of the driving roller is in contact with a piece of paper for grabbing the piece of paper. After the piece of paper has been grabbed, the piece of paper is conveyed by the paper-feeding roller. The driving roller of the paper-grabbing roller set stops with the non-semicircular part facing the paper, thus, when the paper-feeding roller set receives and conveys the paper, the driving roller of the paper-grabbing roller set is not in contact with the paper. However, in such design, since only a half of the periphery of the driving roller is used to be in contact with paper, the distance for the driving roller of the paper-grabbing roller set conveying papers is limited, thus, in order to enlarge the distance, the size of the driving roller must be increased, or the distance between the paper-grabbing roller set and the paper-feeding roller set must be reduced to make them be joined together, which also causes a limitation in the design.

Moreover, as for the driving roller of the paper-grabbing roller set with a shape of a cylinder, a one-way clutch bearing or a spring is required to connect the driving roller with its driving device, such as a motor, so as to prevent the interference between the paper-grabbing roller set and the paper-feeding roller set when taking paper. That is, when the piece of paper conveyed by paper-grabbing roller set reach the paper-feeding roller set, the driving roller of the paper-grabbing roller set is set in an idle state to prevent the interference between the paper-grabbing roller set and the paper-feeding roller set. However, this design has the defects of being complicated, and difficult for assembling.

SUMMARY OF THE INVENTION

The paper-grabbing roller sets in the conventional art in order to prevent the interference between the paper-grabbing roller set and the paper-feeding roller set have disadvantages, such as complicated structures, being difficult for assembling, and having too many limitations in the design. In view of the above problems, an object of the present invention is to provide a driving roller assembly for a paper feeding apparatus, which is simple in structure, easy for being manufactured and assembled, and thereby achieving the effect that the paper-grabbing roller set doesn't interfere with the paper-feeding roller set.

In order to achieve the aforementioned object, the present invention provides a driving roller assembly for a paper feeding apparatus, which drives a driving roller with a shaft to rotate. The driving roller assembly includes a transmitting sleeve, a one-way coupling sleeve, and a driven block.

The transmitting sleeve is slid over the shaft and has a notch being disposed on one end, wherein a canted edge is formed in the notch and has an inclined angle with respect to a rotational axis of the driving roller.

The one-way coupling sleeve is slid over the shaft, and is adjacent to the transmitting sleeve. The one-way coupling sleeve has a first one-way coupling end and an actuating end. The actuating end is inserted into the notch and is slidably contacted with the canted edge, so as to move the one-way coupling sleeve along the rotational axis of the shaft; and the actuating end moves back and forth within the notch along the tangential direction of the shaft. Then, as the actuating end is engaged with one side of the notch, the transmitting sleeve drives the one-way coupling sleeve to rotate.

The driven block is fixed to the shaft, and has a second one-way coupling end corresponding to the first one-way coupling end of the one-way coupling sleeve. The first one-way coupling end is coupled to the second one-way coupling end in one rotational direction only, that is, the first one-way coupling end is coupled to the second one-way coupling end in a first rotational direction, and it is released there-from in a second rotational direction opposite to the first rotational direction.

When the transmitting sleeve rotates along the first rotational direction, the transmitting sleeve presses against the canted edge to move the one-way coupling sleeve towards the driven block, such that the first one-way coupling end is coupled to the second one-way coupling end. Meanwhile, the actuating end of the one-way coupling sleeve presses against one side of the notch, such that the one-way coupling sleeve, is driven to rotate in the first rotational direction, and thereby, the driven block and the shaft are driven to rotate in the first rotational direction. When the transmitting sleeve stops rotating, but the shaft still rotates in the first rotational direction, or when the rotational speed of the shaft in the first rotational direction is higher than that of the transmitting sleeve, that is, the transmitting sleeve rotates along the second rotational direction relative to the shaft and the driven block. At this time, the coupling between the first one-way coupling end and the second one-way coupling end is released. Thus, the shaft rotates separately, without interfering with the transmitting sleeve and the one-way coupling sleeve.

The advantage of the present invention lies in that, the present invention is applicable to a paper-grabbing roller set of a paper feeding apparatus to prevent the interference between the paper-grabbing roller set and the paper-feeding roller set. Compared with the structure of the paper-grabbing roller in the conventional art, the structure of the present is simpler and is easy to be manufactured and assembled.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below for illustration only, which thus is not limitative of the present invention, and wherein:

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a top view of the embodiment of the present invention.

FIGS. 3 and 4 are enlarged schematic views of parts of the embodiment of the present invention.

FIG. 5 is a top view of the embodiment of the present invention in another aspect.

DETAILED DESCRIPTION OF THE INVENTION

The driving roller assembly provided by the present invention is applied in a paper feeding apparatus, which can be but not limited to printers, paper-feeding scanners, or multifunctional printers.

FIGS. 1 and 2 are respectively a perspective view and a top view of an embodiment of the present invention. A first driving roller 210 and a second driving roller 220 are disposed in the paper feeding apparatus with a rotational axis parallel to that of each other. The first driving roller 210 is a part of a paper-grabbing roller set of the paper feeding apparatus, and the second driving roller 220 is a part of a driven roller set of the paper feeding apparatus. The first driving roller 210 is provided for grabbing a piece of paper 700 from a paper- tray (not shown), and conveying the piece of paper 700 to the second driving roller 220. The second driving roller 220 is provides for receiving the piece of paper 700 conveyed by the first driving roller and then conveying the piece of paper, such that the piece of paper is continuously conveyed in a paper track of the paper feeding apparatus. Generally, the rotational speed of the second driving roller 220 is higher than that of the first driving roller 210, such that a fixed interval is formed between the two pieces of paper due to the rotational speed difference. When the front edge of the paper 700 reaches the second driving roller 220, the driving power output for the first driving roller 210 is stopped.

The driving roller assembly of the present invention is provided for driving the first driving roller 210 rotating about a rotational axis X. A shaft is disposed at the rotational axis X of the first driving roller 210, so as to fix the first driving roller 210 to a predetermined position corresponding to an inlet of the paper track of the paper feeding apparatus. The driving roller assembly includes a transmitting sleeve 400, a one-way coupling sleeve 500, and a driven block 600. The details are described as follows.

Referring to FIGS. 3 and 4, the transmitting sleeve 400 is slid over the shaft 300, and has a canted edge 410 formed at one end thereof and a driven part 430 opposite the canted edge 400 formed at the other end of the transmitting sleeve 400. The canted edge 410 has an inclined angle with respect to the rotational axis X. One end of the canted edge 410 extending towards outside of the transmitting sleeve 400 along the rotational axis X is formed into a first stopper 421, and the other end of the canted edge 410 extending towards inside of the transmitting sleeve 400 along the rotational axis X is formed into a second stopper 422. A notch 420 is formed between the first stopper 421 and the second stopper 422, and the canted edge 410 is just located within the notch 420. The driven part 430 can be a gear for connecting to a first driving device 920 (e.g., a motor), such that the transmitting sleeve 400 is driven by the first driving device 920.

The one-way coupling sleeve 500 is slid over the shaft 300, and has a first one-way coupling end 510 and an actuating end 520. A slide block 521 is protruded from the actuating end 520, which is slidably contacted with the canted edge 421 and to presses against the first stopper 421. When the transmitting sleeve 400 rotates along a first rotational direction, the actuating end 520 slides relative to the canted edge 410, and moves the one-way coupling sleeve 500 to away from the transmitting sleeve 400 along the rotational axis X, and the first stopper 421 presses against the slide block 521 of the actuating end 520, such that the actuating end 520 is engaged with the first stopper 421 and then the transmitting sleeve 400 drives the one-way coupling sleeve 500 to rotate. When the transmitting sleeve 400 rotates along a second rotational direction opposite to the first rotational direction, the one-way coupling sleeve 500 is released and not rotated.

The driven block 600 is fixed to the shaft 300, and has a second one-way Coupling end 620 corresponding to the first one-way coupling end 510 of the one-way coupling sleeve 500. The first one-way coupling end 510 is coupled to the second one-way coupling end 620 in one rotational direction only, such that the one-way coupling sleeve 500 is coupled to the driven block 600 to drive the shaft 300 to rotate in one rotational direction only. Specifically in the embodiment of the present invention, the first one-way coupling end 510 is coupled to the second one-way coupling end 620 in the first rotational direction, and it is released from the second one-way coupling end 620 in the second rotational direction opposite to the first rotational direction. Therefore, when the one-way coupling sleeve 500 rotates in the first rotational direction, it drives the driven block 600; and when the one-way coupling sleeve 500 rotates in the second rotational direction, it doesn't move together with the driven block 600. When the one-way coupling sleeve 500 rotates in the first rotational direction together with the transmitting sleeve 400, the one-way coupling sleeve 500 is moved away from the transmitting sleeve 400, such that the first one-way coupling end 510 presses against the second one-way coupling end 620, and the first one-way coupling end 510 and the second one-way coupling end 620 are coupled with each other in the first rotating direction, as shown in FIG. 4.

Referring to FIGS. 2, 3, and 5, FIG. 5 shows the cooperation of the first driving roller 210 and the second driving roller 220. The first driving device 920 is connected to the driven part 430, and further drives the transmitting sleeve 400 to rotate, and moves the one-way coupling sleeve 500 to be coupled to the driven block 600, and thereby driving the first driving roller 210 to rotate. At meanwhile, the piece of paper 700 is conveyed by the first driving roller 210 towards the second driving roller 220. A trigger element 800 is disposed in advance of the second driving roller 220 for detecting the arrival of the front edge of the piece of paper 700 to be received by the second driving roller. Once the front edge of the paper 700 is detected by the trigger element 800, a second driving device 940 immediately outputs power to drive the second driving roller 220 to rotate. At the same time, the first driving device 920 is stopped driving the transmitting sleeve 400. In the paper feeding apparatus, the paper feeding rate of the second driving roller 220 must be higher than that of the first driving roller 200, or when the second driving roller 220 is contacted with the paper 700, the first driving device 920 must be stopped. The first driving roller 210 is driven by the piece of paper 700 and rotates at a speed higher than the speed of the transmitting sleeve 400, thus, the driven block 600 rotates in the second rotational direction relative to the one-way coupling sleeve 500 and the transmitting sleeve 400. Thus, the driven block 600 is not coupled to the one-way coupling sleeve 500, such that the rotation of the driven block 600 doesn't interfere with the first driving device 920, the transmitting sleeve 400, and the one-way coupling sleeve 500. Accordingly, the paper 700 is conveyed into the paper feeding apparatus through the second driving device 940 and the second driving roller 220 at a speed higher than the paper feeding rate of the first driving roller 200. The predetermined interval between two pieces of paper can be maintained due to the different speeds for the first driving roller 210 and the second driving roller 220 to convey the piece of paper 700.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious-to one skilled in the art are intended to be included within the scope of the following claims. 

1. A driving roller assembly for a paper feeding apparatus, for driving a driving roller conveying a piece of paper, wherein a shaft is disposed at a rotational axis of the driving roller, the driving roller assembly comprising: a transmitting sleeve, slid over the shaft, and having a canted edge formed at one end thereof, wherein the canted edge has an inclined angle with respect to the rotational axis of the driving roller, and one end of the canted edge extending towards outside of the transmitting sleeve along the rotational axis is formed into a first stopper; a one-way coupling sleeve, slid over the shaft, and having a first one-way coupling end and an actuating end, wherein the actuating end is slidably contacted with the canted edge to move the one-way coupling sleeve along the rotational axis, and the actuating end is provided for being engaged with the first stopper, such that the transmitting sleeve drives the one-way coupling sleeve to rotate; and a driven block, fixed to the shaft, and having a second one-way coupling end corresponding to the first one-way coupling end of the one-way coupling sleeve, wherein the first one-way coupling end is coupled to the second one-way coupling end in one rotational direction only, and the shaft is driven to rotate by coupling the one-way coupling sleeve to the driven block.
 2. The driving roller assembly for a paper feeding apparatus as claimed in claim 1, wherein the first one-way coupling end one-way coupling sleeve is coupled to the second one-way coupling end of the driven block in a first rotational direction, and it is separated from the second one-way coupling end in a second rotational direction opposite to the first rotational direction.
 3. The driving roller assembly for a paper feeding apparatus as claimed in claim 2, wherein when the transmitting sleeve rotates in the first rotational direction, the transmitting sleeve presses against the canted edge of the actuating end to move one-way coupling sleeve towards the driven block, and thereby the first one-way coupling end is coupled to the second one-way coupling end.
 4. The driving roller assembly for a paper feeding apparatus as claimed in claim 1, wherein an end of the canted edge towards inside of the transmitting sleeve along the rotational axis is formed into a second stopper.
 5. The driving roller assembly for a paper feeding apparatus as claimed in claim 4, wherein a notch is formed between the first stopper and the second stopper, and the canted edge is located within the notch.
 6. The driving roller assembly for a paper feeding apparatus as claimed in claim 1, wherein a slide block is protruded from the actuating end, and the slide block is slidably contacted with the canted edge, to presses against the first stopper.
 7. The driving roller assembly for a paper feeding apparatus as claimed in claim 1, wherein the other end, away from the canted edge, of the transmitting sleeve is connected to a driving device, and driven by the driving device.
 8. A paper feeding apparatus, comprising: a first driving roller, for conveying a piece of paper, wherein a shaft is disposed at a rotational axis of the first driving roller; a transmitting sleeve, slid over the shaft, and having a canted edge formed at one end thereof, wherein the canted edge has an inclined angle with respect to the rotational axis of the driving roller, and one end of the canted edge extending towards outside of the transmitting sleeve along the rotational axis is formed into a first stopper; a one-way coupling sleeve, slid over the shaft, and having a first one-way coupling end and an actuating end, wherein the actuating end is slidably contacted with the canted edge and drives the one-way coupling sleeve to move along the rotational axis, and the actuating end is provided for being engaged with the first stopper, such that the transmitting sleeve drives the one-way coupling sleeve to rotate; a driven block, fixed to the shaft, and having a second one-way coupling end corresponding to the first one-way coupling end of the one-way coupling sleeve, wherein the first one-way coupling end is coupled to the second one-way coupling end in one rotational direction only, and the shaft is driven to rotate by coupling the one-way coupling sleeve to the driven block; and a second driving roller, disposed with a rotational axis parallel to that of the first driving roller, for receiving the piece of paper conveyed by the first driving roller and then conveying the piece of paper, such that the piece of paper is continuously conveyed.
 9. The paper feeding apparatus as claimed in claim 8, further comprising a trigger element for detecting the arrival of a front edge of the piece of paper to be received by the second driving roller.
 10. The paper feeding apparatus as claimed in claim 8, further comprising a first driving element and a second driving element, wherein the first driving element is provided for driving the transmitting sleeve to rotate, and the second driving element is provided for driving the second driving roller to rotate. 